P0624 Fuel Cap Lamp Control Circuit

P0624 points to a fuel cap lamp control circuit issue. The controller cannot command or monitor the warning lamp or indicator used for fuel cap or EVAP messages.

Code details

Generic OBD-II · P0

System: Computer
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the fuel cap for P0624 unless EVAP leak or seal faults are also confirmed.

Symptoms of P0624

Check-engine light, sometimes with several unrelated codes at once.
Warning lights, a no-start, or intermittent electrical faults.
Communication or module-reset problems on a scan tool.

Common causes of P0624

Low battery voltage, poor grounds, corroded connectors, or blown fuses.
Wiring or network (CAN bus) faults between modules.
A module software/programming issue, or rarely a failed controller.

Useful checks before replacing parts

Check fuel cap lamp command, cluster indicator status, EVAP fault history, communication faults, freeze-frame data, and related lamp control codes.
Inspect cluster wiring, lamp driver circuits, module connectors, fuses, grounds, and networked warning message paths where applicable.
Verify the lamp or message can be commanded on and off separately from the EVAP leak diagnosis itself.

Related OBD-II codes

These nearby computer entries can help compare wording and pin down the fault area.